General General 6 min read

Into the wild

Boost your animal instincts with 10 fascinating mammals that roam America

Image: christie greene

Mammals form one of the greatest classes of vertebrate animals. There are more than 5400 known species of mammals in the world, and more than 400 of these species are found in the United States. From terrestrial to aquatic, carnivorous to herbivorous, we have some of the most interesting mammals on the planet. In this article, we have chosen 10 animals that, due to their special characteristics, are already an essential part of our culture. Can you guess which ones they are?

1
Grizzly Bear

Image: Joshua J. Cotten

Grizzly bears ( Ursus arctos horribilis ) are one of the most famous North American mammals, but do you know why they are called that? The grizzly bear is a subspecies of the brown bear. However, although grizzlies are mostly brown, their fur can appear white-tipped or grizzled , which explains their name.

The grizzly bear once lived throughout much of the North American West. Unfortunately, the arrival of Europeans gradually drove it from its original habitat, considerably reducing its population. In 1975, they were listed as threatened under the U.S. Endangered Species Act, and much has been done since then to protect the species. Today, grizzlies can still be found in parts of Wyoming, Montana, Idaho, Washington, and the Alaskan wilderness. They are also one of the most iconic residents of Yellowstone National Park.

2
Gray Wolf

Image: Yannick Menard

We all know that wolves are legendary for their eerie howl, but there are many other interesting facts about this peculiar animal. Gray wolves ( Canis lupus ) are the largest members of the dog family and are native to North America and Eurasia. The size of an adult gray wolf is similar to that of an average dog and it can weigh up to 145 pounds. However, their tracks would outshine those of any dog, as they measure about 5 inches long by 4 inches wide.

Wolves live and hunt in packs of 6 to 10 animals. They are known to travel great distances, even covering 30 miles in a single day. In the United States, gray wolves were hunted to near extinction, although some populations survived and others have since been reintroduced. Today gray wolves can be found in areas such as the Great Lakes states of Minnesota, Wisconsin, and Michigan, the northern Rocky Mountains region, and the northwest.

3
North American River Otter

Image: lovelooking

The North American River Otter ( Lontra canadensis ) is a species of semi-aquatic, carnivorous mammal endemic to the North American continent that can be found along the coasts and rivers of the United States and Canada. Because they are very susceptible to environmental pollution, their population has been reduced considerably in recent years.

It is a mostly nocturnal animal, often seen at dusk or dawn. During the day it takes refuge in burrows with an underwater entrance that leads to a nest chamber lined with plant material and hair. North American River Otters are robust (11 to 31 pounds) and feed on fish and other aquatic prey, such as turtles, frogs, and crabs.

4
Red Fox

Image: Jeremy Hynes

The red fox ( Vulpes vulpes ) is a species of mammal in the canid family. It is the most abundant fox species in the northern hemisphere and can be found in many national parks across the country. As its name suggests, its fur is reddish in color. The tips of the ears and the ends of the legs, however, are black. They have a bushy tail whose tip is usually white, as is their belly.

Although classified as a carnivore, the red fox is actually an omnivore and, above all, a great opportunist. They are astute, have excellent eyesight, and have a keen sense of smell and hearing. They can hunt prey of a wide variety of sizes, from insects and worms to small mammals, birds, and fish. They also feed on certain vegetables, berries, and fruits.

5
Mountain Lion

Image: Robert Sachowski

The cougar ( Puma concolor ), also known as the mountain lion, is a mammal native to the Americas. These large, tan cats are found from the Yukon in Canada to the southern Andes Mountains and Patagonia in South America. In the United States, mountain lions can be found mainly in the western part of the country. However, because of their solitary nature and constant threats from humans, it is difficult to estimate exact population numbers.

Mountain lions are slender and agile felines that can adapt to different conditions and environments. They are strict carnivores and have extraordinary vision and acute hearing, which allows them to capture almost any animal, from insects to squirrels, beavers, elk, and deer.

6
North American Beaver

Image: kidmoses

Beavers are known to be one of the only animals that can affect the ecosystem around them, building watertight dams that help preserve water in streams and rivers. The North American beaver ( Castor canadensis ) is the largest rodent in North America and one of the largest in the world —it can weigh between 24 and 71 pounds! The species is widely distributed throughout the continent, from northern Canada to northern Mexico.

The North American beaver's coat can range from dark brown to reddish brown, and its most distinctive feature, a flattened paddle-shaped tail, allows it to swim. It is perfectly adapted to semi-aquatic life; its ears and nose have valves that close when submerged, and it can close its lips behind its prominent incisors to cut wood underwater.

7
Hawaiian Monk Seal

Image: Sebastian Coman Travel

The Hawaiian Monk Seal ( Neomonachus schauinslandi ) is a species native to the Hawaiian Islands. With its friendly face and long whiskers, it is perhaps one of the most endearing mammals that can be found in our country. Unfortunately, this seal species is endangered because of the large amount of chemical waste produced by the fishing industry on the reefs and beaches of the northern Pacific Ocean.

The Hawaiian Monk Seal is usually solitary but is always seen accompanied by other specimens. It is known to be piscivorous, that is, it feeds mainly on fish and other marine creatures, such as crustaceans and some species of mollusks. Since it is a predator by nature, when hunting it makes the most of its length (approximately 7 feet) and its large body (between 300 to 600 lb) to catch its prey.

8
American Red Squirrel

Image: Rusty Watson

The American red squirrel ( Tamiasciurus hudsonicus ) lives in the United States and much of Canada. It is a rodent mammal easily recognized for its deep reddish fur, long bushy tail, and prominent lower teeth. It can be differentiated from other North American squirrel species because of its smaller size, 11 to 14 inches.

American red squirrels normally live in the shady areas of coniferous forests and are primarily granivores. They feed on seeds, pine cones, nuts, fruit, and occasionally insects, eggs, and birds. It is mainly active in trees but also swims freely, using its tail as a rudder to change its direction.

9
Elk

Image: Judy Beth Morris

Elk ( Cervus canadensis ), also known as wapiti in several Native American cultures, is a species of deer that lives in North America, Central and East Asia. Today, most elk in our country are found primarily in the West, especially in mountainous regions such as Wyoming's National Elk Refuge and Yellowstone National Park. Some eastern states have also reintroduced small herds into natural forest areas.

The most prominent feature of elks is their massive antlers. Each March they shed their antlers, which begin to grow back in May to be ready for the breeding season in late summer. During this time the bellowing of the males echoes through the mountains, announcing the violent battles that serve to decide who mates with whom. The males with the largest antlers, usually the oldest, often win these duels and get to dominate the herd.

10
American Bison

Image: Stephen Leonardi

The American bison is a true symbol of American identity. Not only is it the largest mammal in North America, it is also the national mammal of the United States. In addition, it's one of the greatest conservation success stories of all time.

In prehistoric times, there were millions of specimens of American bison ( Bison bison ) roaming our territory. But by the late 19th century, there were only a few hundred left. Fortunately, thanks to the efforts of several organizations and individuals, the species was reintroduced and today it can be found in a few national parks and reserves as well as in the wild.

Geography Geography 5 min read

Exploring the underworld

Would you explore a cemetery's catacombs? 10 underground must-sees

Image: Blake Cheek

We sometimes forget there is a whole world going on beneath our feet. Hidden from view lie underground marvels like caves hosting weddings, crystal-clear freshwater pools, and sidewalks of cities that no longer exist. Here, we explore 10 must-see underground sites in the U.S. Grab your flashlight, and let’s venture below the surface!

1
Seattle Underground City

Did you know the remnants of Seattle's original streets are still accessible? Beneath the bustling streets of modern-day Seattle lies the Underground City , a network of subterranean passageways that formed the ground level in the 1800s.

By the end of the 19th century, after the Great Seattle Fire, it was decided to rebuild the city at a higher elevation to combat frequent flooding . So, these original streets, sidewalks, and storefronts were buried, and with it, much of their history.

Guided tours take people through tunnels and ladders and retell real and eerie stories about the history of the Underground City.

2
Luray Caverns

Image: Robert Thiemann

Have you ever heard of the underground Stalacpipe Organ ? Not only is it a one-of-a-kind interaction between keyboards and cavern stalactites, but it is also the largest musical instrument in the world, according to Guinness World Records.

This instrument lives in the Luray Caverns, Virginia. It consists of an electric console that taps on these ancient stalactites of varying sizes to produce musical tones. A subterranean wonder, these caverns are also known for their extraordinary size , housing towering stalactites and stalagmites, mirrored pools, and delicate drapery-like calcite formations.

3
The Underground Gardens of Baldassare Forestiere

Image: Adrian Botica

This stunning subterranean retreat was built entirely by hand. Tucked under the sun-scorched landscape of Fresno, California, lie the Underground Gardens of Baldassare Forestiere . They are the life’s work of Baldassare Forestiere, a Sicilian immigrant who started digging in the early 1900s to escape the Central Valley's oppressive heat.

Over 40 years, drawing inspiration from ancient Roman catacombs , Forestiere carved an elaborate network of underground rooms, passageways, grottoes, and courtyards that span 10 acres.

A unique masterpiece, the gardens are open with guided tours that lead guests through beautifully designed spaces featuring skylights, arches, and alcoves. This oasis also boasts an array of fruit trees, including citrus, figs, and olives.

4
Ruby Falls

Image: Goodfreephotos_com

Colorful and breathtaking, the Ruby Falls is a geological wonder located inside Lookout Mountain near Chattanooga, Tennessee.

Hidden over 1,000 feet below the mountain's surface, this waterfall cascades 145 feet into a pool , making it one of the tallest underground waterfalls open to the public.

Visitors enter the mountain and descend via elevator. Then, they walk through stunning cave formations such as stalactites, stalagmites, and flowstone. At the waterfall chamber, multicolored lights –powered by renewable energy– illuminate the falls. Lantern-lit tours are also offered as a chance to visit the marvel with a different charm.

5
The Catacombs of Green-Wood Cemetery

Image: Joy Ernst

Arched tunnels of tranquil, sacred vaults lie beneath the Green-Wood Cemetery in Brooklyn, New York. Built in the mid-19th century, these catacombs were designed as a prestigious resting place for the city’s elite , prominent families.

While the catacombs are typically closed to the public, special events are sometimes organized to welcome visitors, such as art expositions, guided history tours, and candlelit tours seasoned with live music and storytelling.

Outside, where the sun does reach, await the serene landscapes and remarkable monuments of the cemetery, which is itself a National Historic Landmark .

6
The Lost Sea

Image: Roberto Nickson

The largest underground lake in America is in Tennessee. Hidden within the Craighead Caverns in Sweetwater, this enormous body of water lies in a cave system filled with fascinating formations, such as stalactites, stalagmites, and rare anthodites, also known as "cave flowers."

A National Natural Landmark, this lake marvels scientists, who are yet unaware of the exact extension of its waters. Those who visit can embark on a boat ride called "The Lost Sea Adventure," first walking inside the cavern before reaching a boat to navigate these ethereal sights.

7
Mammoth Cave National Park

Image: Sherin Jacob

The Mammoth Cave National Park is home to the longest cave system in the world . Located in central Kentucky, it extends over 420 miles of explored passages and many more likely undiscovered. Enormous chambers, underground rivers, a labyrinth of tunnels, and gypsum crystal formations can all be found at this site.

The park has been declared a UNESCO World Heritage Site and an International Biosphere Reserve. It also includes over 52,000 acres of protected land on the surface, renowned for its lush forests and diverse wildlife.

8
Carlsbad Caverns National Park

Image: Cason Asher

A large bat colony lives in the Carlsbad Caverns National Park in New Mexico, but that’s not its only charm. The park boasts over 100 caves, with its centerpiece being the immense Carlsbad Cavern.

The cavern includes the Big Room, one of the largest underground chambers in North America, spanning 8.2 acres. Visitors can descend via an emblematic natural entrance or by elevator, dropping 750 feet underground. Stalactite formations like the Giant Dome, the Hall of the White Giant, and the Chandelier are some of the caves' breathtaking highlights.

9
Indian Echo Caverns

Image: Magda Ehlers

The Indian Echo Caverns, which have been open to the public since the early 1920s, are carved into the limestone of the Appalachian Mountains. Located near Hummelstown, Pennsylvania, this site gets its name from the echoes heard within the cavern’s chambers , which were once believed to be mystical by Native American people in the area.

Unique, immersive sections of the caverns have names like the "Crystal Palace," the "Echo Room," and the "Wedding Room," where, yes, real weddings are sometimes held!

10
Wind Cave National Park

Image: Francesco Ungaro

Wind Cave National Park, located in the Black Hills of South Dakota, is one of the world’s largest caves, but that’s not what it’s most famous for. One signature sight here is the boxwork formation , a rare lattice-like pattern formed by calcite deposits.

The cave system stretches for over 140 miles, though much of it remains unexplored. Popular tours take guests through captivating features like the "Ribbon Room" and the "Crystal Palace."

Why is Wind Cave called that? Mainly due to the "wind" phenomenon that occurs at its entrance. The cave's air pressure causes the entrance to draw in or expel air, depending on atmospheric conditions.

Geography Geography 5 min read

Unparalleled sights

Have you ever seen these geological oddities found only in the US?

Image: Steve Wrzeszczynski

Hot springs painted like rainbows, diamond-handpicking lands, and a mysterious disappearing waterfall—these are some of the unique geological spots you can find only in the U.S. Surreal rock and mineral formations, like the Petrified Forest or the Fly Ranch Geyser, have acquired their vibrant colors over decades or even millennia and are still there, waiting to be marveled at by hikers and visitors. Have you ever seen or read about these one-of-a-kind marvels? Let’s dive into how they came to be!

1
Grand Prismatic Spring

Image: MikeGoad

The steaming, multicolored circle of the Grand Prismatic Spring is one of the most hypnotic and unique sights in the U.S. Part of Yellowstone National Park, this hot spring is the largest in the country and the third-largest in the world, measuring 370 feet wide and 160 feet deep.

Its vibrant colors, ranging from deep blue in the center to fiery red and orange at its edges, are unlike anything we see in nature every day. Minerals and microbes are responsible for these hues, with water temperature causing the pigments to fluctuate . The spring owes its existence to geothermal activity driven by Yellowstone's underlying magma chamber and is located in the Midway Geyser Basin.

2
Fly Ranch Geyser

Image: Ken Lund, CC BY-SA 2.0

One of the reasons why Fly Ranch Geyser is unique in the world is that it was formed after a human accident . This technicolor geothermal geyser, located on the Fly Ranch property in the Hualapai Geothermal Flats of Washoe County, Nevada, wasn’t there before 1916.

In 1916, while drilling a well for irrigation in the area, workers struck near-boiling geothermal water, leading to the creation of the first geyser. Decades later, in 1964, a geothermal energy company drilled a second well nearby, which caused the emergence of the Fly Geyser we know today. It has been spouting water into the sky ever since, forming several cone-like vents atop a mound that continues to grow.

3
Devil’s Kettle

Image: chrishawaii

Where does the water from the Brule River go when it falls? For a long time, this was a mystery. Located in Judge C.R. Magney State Park near Grand Marais, Minnesota, along the North Shore of Lake Superior, the river is famous for its unusual split: one half flows downstream, while the other plunges into a seemingly bottomless hole .

This waterfall has baffled visitors and scientists for years because objects thrown into the "kettle," such as logs and ping-pong balls, appeared to vanish without resurfacing. This fueled theories of underground rivers or deep caverns beneath the falls. The mystery was solved recently when hydrologists discovered that the water entering the kettle resurfaces downstream . The kettle's strong currents explain why objects thrown in don’t resurface; they are broken apart and held underwater, functioning like a natural washing machine.

4
Mono Lake Tufa Towers

Image: Stephen Leonardi

These unique limestone formations, known as the Mono Lake Tufa Towers, emerge from the salty, alkaline waters of Mono Lake , fed by underwater springs. Located in eastern California, near the Sierra Nevada mountains and about 13 miles east of Yosemite National Park, they are a striking natural wonder.

These tufa towers rise dramatically from the water. How were they formed? Mono Lake has no outlet, so its high alkalinity and salinity caused minerals to accumulate over time. This unique environment supports an ecosystem of brine shrimp, alkali flies, and migratory birds. To give you an idea, the lake’s salinity is more than twice that of the ocean, which means you could float effortlessly in its waters, as many visitors do.

5
Crater of Diamonds

Image: Brett Sayles

If you find a diamond here, you get to keep it—this is the only diamond-bearing site in the world where that's possible. Open to the public for mining , the Crater of Diamonds is a 37.5-acre field located near Murfreesboro, Arkansas. It marks the eroded surface of a volcanic pipe composed of lamproite, a rare volcanic rock.

Visitors sometimes find diamonds of various colors, including white, yellow, and brown, along with other gems like amethyst and garnet. It was here that the "Uncle Sam Diamond" was found, the largest diamond ever dug out in North America, weighing 40.23 carats. Diamonds were first discovered here in 1906 when a local farmer found unusual crystals on his land, which sparked a minor diamond rush.

6
Antelope Canyon

Image: Roberto Lee Cortes

Rocks that look like flowing water: Antelope Canyon is a famous and breathtaking slot canyon in northern Arizona. It consists of two main sections: Upper Antelope Canyon (a.k.a. Tsé bighánílíní, or "the place where water runs through rocks") and Lower Antelope Canyon ( Hazdistazí, or "spiral rock arches").

The canyon was formed over millions of years as flash floods and desert winds eroded the Navajo Sandstone. Even today, seasonal flash flooding continues to shape and carve the canyon’s mesmerizing features. Its surreal, wave-like formations in shades of orange are a favorite subject for photographers and tourists from all over the world.

7
Petrified Forest

Image: Megan Clark

The Petrified Forest National Park in northeastern Arizona boasts one of the world's largest and most vibrant concentrations of petrified wood . The park, part of the Painted Desert, is located between the Apache and Navajo Counties.

Most of the wood found there is from ancient conifer trees that date back about 225 million years to the Late Triassic period. These trees were swept into river systems, buried by sediment, and transformed into stone through a process called permineralization . The park also features a wealth of fossilized remains of ancient animals, including early reptiles.

8
Devils Tower

Image: Kyle Petzer

The Devils Tower stands alone, protruding dramatically from the plains. Considered sacred by Native American tribes, it was originally called "bad god’s tower," a name that eventually evolved into its current form. Located in northeastern Wyoming, this igneous rock monolith soars 867 feet above its base.

It was designated the first U.S. National Monument by President Theodore Roosevelt in 1906. Geologists agree that Devils Tower was formed through the intrusion of magma into sedimentary rock layers about 50 to 60 million years ago. Today, climbers from around the world are drawn to its sheer walls, though climbing is prohibited in June to honor Native ceremonies.

9
The Wave

Image: Mark Nemenzo

The Wave is a visually stunning sandstone formation located in the Coyote Buttes North area of the Vermilion Cliffs National Monument. Known for its hypnotic, swirling bands of red, orange, and yellow, its delicate ridges are so easily damaged that even one misplaced footstep could ruin the beautiful patterns.

Approximately 185 million years ago, this area was a vast desert covered in dunes. Over time, layers of sand were deposited, compacted, and cemented, forming this Navajo sandstone shape. Unfortunately, The Wave is only accessible by a challenging hike that requires a permit, due to the fragility of its ecosystem and high demand from visitors. With less than 5% of applicants obtaining a permit each year, it is one of the most exclusive hiking destinations in the world.

10
Kasha-Katuwe Tent Rocks National Monument

Image: Bruce Warrington

The Kasha-Katuwe Tent Rocks National Monument, located in northern New Mexico, displays a unique landscape of tall, cone-shaped rock formations. These "tent rocks," composed of pumice and tuff, are known as "hoodoos." They are natural formations ranging from a few feet to approximately 90 feet tall.

The name "Kasha-Katuwe" means "white cliffs" in the Keresan language of the Cochiti Pueblo. Hiking trails, such as the Slot Canyon Trail, offer visitors the opportunity to explore the cones up close while walking through dramatic, narrow canyons.

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